1. Technical Field
The present invention relates to a mixed coating material, a wing, and an anti-icing system, in particular, to a technique that enables effective anti-icing for wings of aircraft, for example.
2. Related Art
Anti-icing equipment is conventionally provided in aircraft for the purpose of preventing icing or the progress of icing in airframes. Examples of such anti-icing equipment include thermal anti-icing equipment relying on engine bleed air or electricity, pneumatic deicing equipment relying on deicing boots, and chemical deicing equipment using alcohol. The role of anti-icing equipment in aircraft is to prevent icing or the progress of icing in the airframe, to avert thereby wasteful consumption of airframe fuel during flight, on account of hampering of smooth flow of air around the airframe, and increased air resistance derived from a reduction in wing lift, caused by icing.
Even in aircraft provided with anti-icing equipment, however, there are portions where icing cannot be completely controlled in practice by the anti-icing equipment, i.e. some icing occurs at portions beyond the anti-icing equipment capabilities. This inability of combating formation and growth of ice at portions, in the airframe, beyond the anti-icing equipment capabilities exerts a significant negative impact in terms of wasteful consumption of aviation fuel, due to the increased resistance during flight at those portions that lie outside the reach of the anti-icing equipment capabilities.
In order to solve this problem, it would be conceivable to increase the scale of the anti-icing equipment, or to run the anti-icing equipment more intensively, also for portions in the airframe that lie outside the reach of the anti-icing equipment capabilities, such as antennas, flap hinges, control horns and the like. However, this approach of extending the anti-icing effect elicited by the anti-icing equipment to portions beyond the anti-icing equipment capabilities has been thus far difficult to realize, on account of the increased airframe weight that results from increasing the scale of the anti-icing equipment, and the consumption of airframe fuel incurred in running the anti-icing equipment more intensively, all of which translates, contrarily, into yet greater consumption of the limited airframe fuel.
Research is accordingly being conducted to meet the demand of the industry for a coating material that elicits a high anti-icing effect and that enables easy application of the anti-icing effect also to portions in the airframe that lie outside the reach of the anti-icing equipment capabilities, i.e. an anti-icing effect that applies to all airframe surfaces, and such that, when used, the coating material adds little to the weight of the airframe, and does not incur thus wasteful consumption of fuel during flight.
Coating materials having a high anti-icing effect having been proposed thus far include mixed coating materials that enable formation of highly water-repellent coating films, specifically, for instance, a mixed coating material (hereafter referred to as “AIS”) that is obtained by mixing a mixed resin of an ultraviolet curable resin and a tetrafluoroethylene resin, with an organic solvent including a hydrofluorocarbon, in which the hardness of the coating film is 1H or higher (see Japanese Patent No. 3848334). A wing structure (anti-icing system) has also been proposed that has a wing using AIS as a coating material and a heater attached to the wing (see Japanese Unexamined Patent Application Publication (JP-A) No. 2010-234989).
However, AIS is a coating material of ultraviolet curable type, and hence is not easy to use as a coating material for large structures, such as aircraft. In addition, coating films formed of AIS have low durability: specifically, the water-repellency performance tends to degrade due to erosion.